US electric carmaker Tesla Motors Inc on Friday said it will partner with China's No 2 mobile carrier China United Network Communications Corp Ltd to build charging outlets across the country to push sales in the world's biggest auto market.

The companies have signed a deal to build charging posts at 400 China Unicom stores in 120 cities, and will also set up super-charging outlets in 20 Chinese cities, Tesla's China spokeswoman Peggy Yang said.

Tesla's billionaire co-founder Elon Musk has said he expects to invest hundreds of millions of dollars to build charging outlets in China as the company seeks to compete more effectively with foreign rivals such as BMW and Daimler AG and address Chinese customers' complaints about belated product delivery.